Effects of food quality on individual growth and development in the freshwater copepod Boeckella triarticulata

To quantify the demographic effects of food quality, and specifically of the ‘poorquality’ cyanobecterium Anabaena flos-aquae, we reared individual Boeckella triarticulata (Copepoda, Calanoida) on two diets (monospecific Cryptomom sp. versus mixed Cryptomonas-Anabanma diets) and quantified individual growth and developmental trajectories by examining exuviae produced at each molt, from hatching to maturity. Size at molting was less variable among individuals, within and between diets, than age. Food quality had significant effects on male sizes at molting and on stage-specific daily growth rates of both sexes; these effects were strongest during late naupliar and all copepodite stages Tke med Cryptomonas-Anabaena diet significantly slowed development, particularly of copepodite stages. As a consequence of these effects, individuals raised on the mixed diet were smaller and older at maturity. Within a given diet, individual differences explained much, if not most, of the variation exhibited in growth and development. By following growth and development of a large number of individuals throughout their Life cycles, we show that individual females produce variable offspring, indicative of a bet-hedging life-history strategy, and that B.triarticulata (like other calanoids) can grow, develop and survive on diets that include ‘poor quality’ cyanobacteria.